Flags are often used to represent counties, cities and towns. Where these are based on a council's banner of arms they are technically for the use of the council, but they are often used to represent the wider area,  including by official bodies such as the Department for Communities and Local Government .  Northumberland and Hertfordshire County Councils have "released" their banners of arms for use as county flags.  Since 2012 it has been permitted in planning law in England to fly a flag of any British island , county , district , borough , burgh , parish , city , town or village without planning permission as an advertisement. 
The county’s dragon laden folklore is reinforced by its geography, especially in the west, where there is a lonely wild coast, dense woods, wide misty marshes and a low population – ideal habitat for dragons! Many of the stories unsurprisingly originate in this locality. Additionally Somerset was comparatively unaffected by the industrial revolution, populations remained sedentary and the stories have stuck with them. With such a trenchant, dragon filled heritage, the dragon flag that now represents the county of Somerset can be seen as highly appropriate and meaningful.